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(No Model.)

H. DAVIDSON.

FDLDING SQUARE.

No. 318,877. Patented May 26, 1885.

EH aw @mM/NVEIVTOR I Afiornejl W/TNBgES iim NlTED Starts HENRY DAVIDSON, OF BROOKLYN, NEW YORK.

FOLDING SQUARE.

('iPECIE'ICATION forming part of Letters Patent No. 318,877, dated May 26, 1885.

Application filed January 26, 1885. (No model.)

To all whom it may concern.-

Be it known that I, HENRY DAVIDSON, a citizen of the United States and a resident of the city of Brooklyn, Kings county, State of New York, have invented anew and useful Improvement in Rules or Squares for Carpenters, Cloth Measurers, Tailors, etc, of which the following is a specification.

The nature of my invention relates to squares or squaring-rules, whether made of steel, wood, or other material; and itconsists in making the one arm fold upon (edgewise) the other arm, usually the smaller arm to the longer arm,and providing such folding square with a device, serving as a brace to hold the moving arm rigidly at right angles to the other, when extended, and holding it securely to the other when folded. The brace is ar ranged to slide upon the longer arm, and is provided with a spring, which will engage with notches or gains in the edge of the longer arm to keep it in the position thereon as required. It serves to stiffen the joint when extended, as well as holding the small arm at the exact angle.

In the accompanying drawings, Figure 1 is a side view of a square or right-angle rule, the small arm extended, the brace locking it. Fig. 2 is a side view of the same square folded, the brace drawn back and protecting the outer end of the short arm and locked in that position. Fig. 3 is a perspective view of the anglejoint, with the brace in position, looking the short arm at right angles with the oth er arm. Fig. 4 is a perspective of the locking-brace at its second position, drawn back to admit of folding the square. A portion of the long arm is shown with it.

A represents the long arm of the square or right-angle rule, and 13 represents the short arm.

0 represents the brass plates at the joint of the short arm, there being one on each side, so that a groove is formed at D. The joint is pivoted at E, a piece extending out from the long arm between the brass plates 0 completes the joint.

F represents grooves (one on each side) in the long arm, running lengthwise to form tracks or ways to permit of free sliding of the locking-brace.

G represents the locking-brace, the part H straddling or saddling the rule so as to secure it thereto. The edges of this portion are turned in to fit the grooves F of the rule. It is slid on at the end of the rule, the grooves holding it. The edge of the brace at lfits between the brass plates 0 of the short arm, when it is extended,to prevent lateral motion and stiffen the joint, and also between the plates J at its outer end to protect and stiffen its position when folded. A spring at K,

forming a part of the brace, secured thereto by any suitable means, performs the locking of the brace in the positions requisite. Notches in the edge of the arm at L and M are provided, into which the turn (shown at the end of the spring) engages, securing the brace firmly when desired. To permit of sliding the brace it is necessary to throw back the spring and disengage it therefrom.

hat 1 claim, and desire to secure by Letters Patent of the United States, is-

l. A right-anglejointed square or rule having both blades on a plane provided with a self-locking device consisting of a brace and catch-spring, adapted to slide along the edge of one blade, and when pressed into the an gle formed by the two blades extended will lock the blades in that position through the catch'spring fitting or setting into a notch formed in the edge of the blade, upon which the device slides, substantially as shown and described.

2. In combination with a square or rule having arms A and B, the brace G, provided with spring K, arranged and secured thereto, substantially as shown and described.

3. The combination of arms A B, the arm B provided with plates O and groove D, and the arm A provided with grooves 15, with the sliding and self-locking brace G, provided with spring K, all adapted to operate substantially as shown and described.

HENRY DAVIDSON.

Witnesses:

KATIE K. Mnnns, JOHN F. VIcroRY. 

